Abstract
This paper reports a measuring method using transmission grating of the flowvelocity in a microscopic area. The flow velocity is determined from the velocitymeasurement of particle images on the transmission grating placed in front of aphotodetector. These images formed by a microscope objective correspond to particlesmoving in a flowing flui By using the present method, the spatial distribution of flowvelocities in a small glass pipe are measured. The resultant flow velocity distributionsare compared with the theoretical flow distributions known from the volume of waterflowing out from the cell. As a result, it is found that the present method is useful formeasuring the flow velocity in a small probing area having the diameter of 40μmΦ.
